The present invention relates to an information display device for a vehicle, which device is capable of stereoscopically displaying an image containing information for guiding the vehicle or information of circumstances outside the vehicle.
Japanese Laid-open patent publication No. 63-211100 discloses such a conventional method that, when an image of the front crossing is displayed on a screen and a direction of turning left or right at the crossing thereof is indicated by an arrow to guide the vehicle, a pseudo three-dimensional image by means of two-dimensional perspective is used for giving a three-dimensional effect to the object of the image displayed on the screen.
Japanese Laid-open patent publication No. 64-83424 discloses a conventional display device for a vehicle, which device is capable of detecting a current running condition of the vehicle, estimating a future travelling course of the vehicle, preparing a pseudo three-dimensional image of the presumed course by applying a two-dimensional perspective method and by projecting through a projector the prepared image onto a screen provide on a portion of a front glass of the vehicle in such a way that the image may be superimposed on an actual scene ahead of the vehicle.
The problems involved in the above-mentioned conventional method and device are as follows:
The perspective image displaying method can not produce a sufficient three-dimensional image, e.g., of a scene ahead of the vehicle with due impression of distance or of guidance at the crossing with due impression of reality.
The device for projecting a pseudo three-dimensional (two-dimensional perspective) image of a presumed travelling state of the vehicle in the direction of the front glass can not allow an observer to see the image as if it is overlapped on the actual scene ahead of the vehicle with a due impression of distance and space.